Improving Adhesive Properties of Cellulose Nanocrystals Modifying By 3-Glycidoxypropyltrimethoxy Silane (KH-560) Coupling Agents (original) (raw)
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Frontiers in Bioengineering and Biotechnology, 2022
Cellulose nanocrystals (CNCs) have unparalleled advantages in the preparation of nanocomposites for various applications. However, a major challenge associated with CNCs in nanocomposite preparation is the lack of compatibility with hydrophobic polymers. The hydrophobic modification of CNCs has attracted increasing interest in the modern era standing with long challenges and being environmentally friendly. Here, we synthesized CNCs by using cotton as raw material and then modified them with 2-carboxyethyl acrylate to improve their corresponding mechanical, adhesive, contact angle, and thermal properties. Different concentrations (1–5 wt%) of CNCs were used as modifiers to improve the interfacial adhesion between the reinforced CNCs and E-51 (Bisphenol A diglycidyl ether) epoxy resin system. CNCs offered a better modulus of elasticity, a lower coefficient of energy, and thermal expansion. Compared with the standard sample, the modified CNCs (MCNCs) showed high shear stress, high toug...
2021
We synthesized the cellulose nanocrystals (CNCs) by using cotton as a raw material, then it was modified with 2-carboxyethyl acrylate to improve its adhesion and thermal properties. CNCs was chosen as a modifier to improve the interfacial adhesion between the reinforced nanocrystals and E-51 epoxy resin system. This gives a better modulus of elasticity, a lower coefficient of energy, and thermal expansion. Significant improvements in modulus properties, strength, transparency and thermal stability were observed with modified cellulose nanocrystals (MCNCs) compared with the standard sample. SEM, and transmission electron microscope (TEM), powder diffraction (XRD), (TGA and DTG) and Fourier transform infrared spectroscopy (FTIR) were used for the isolation of synthetic (native and modified) cellulose nanocrystals. In addition, the MCNCs adhesion properties with E-51 (Bisphenol A diglycidyl ether) epoxy resins were also investigated using the Zwick/Roell Z020 model.
Adhesive surface interactions of cellulose nanocrystals from different sources
Journal of Materials Science, 2012
Adhesion plays an important role in the final properties of nanocomposites. This study explored the surface interaction of cellulose nanocrystals (CNCs) and the effect of CNC sources on adhesion between individual CNCs and the Si tip of an AFM cantilever using a force mapping technique called FMap. The adhesion between CNCs and a Si tip from five different sources has been studied: cotton, Whatman filter paper, hemp, softwood chemical kraft pulp, and softwood-dissolving pulp (alistaple). Mica was used as the background substrate to act as an internal standard. This study's findings suggest that adhesion is not the same for all CNCs. Transmission electron microscopy and atomic force microscopy were used to determine the size and shape of each CNC. The experimental quantitative data showed that adhesion between CNCs and the Si tip has a close correlation with the diameter of the CNCs. X-ray photoelectron spectroscopy confirmed the presence of sulfate groups on the surface of the CNCs and a correlation between adhesion and surface chemistry of the CNCs was observed.
2015
Cellulose nanocrystals (CNC) from mengkuang leaves (Pandanus tectorius) were investigated as potential reinforcement in poly(vinyl chloride) (PVC) matrix. The surface of CNC was modified with silane coupling agent to improve filler-matrix adhesion. Solution casting method was used to prepare PVC nanocomposites with various amounts of modified (SCNC) and unmodified (CNC) nanocrystals. Both SCNC and CNC were examined by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) which showed that surface chemical modification has occurred. An increase in tensile strength was observed with the addition of SCNC compared to the CNC. However, the elongation at break of the nanocomposites was found to decrease with the increase of both fillers loading. An increasing trend was observed in the tensile modulus with the addition of CNC to the PVC matrix, but decreasing with the addition of SCNC. The morphology of a fractured surface of nanocomposites showed silane modification r...
Journal of Inorganic and Organometallic Polymers and Materials, 2021
Bio-based epoxy resins are being used due to their green chemistry. They have better properties than petroleum-based epoxy resins. Recently, environment friendly nanomaterials have been used for different industrial applications. Cellulose nanocrystals (CNCs) are among the best naturally occurring materials. Therefore, the surface of cellulose nanocrystals are modi ed by eugenol-based silane coupling agent (EBSCA). Chemical composition and surface morphologies of CNCs were analyzed and characterized by FTIR, AFM, SEM, TEM and 1 H-NMR. The SEM and AFM results con rmed eugenol-based silane coupling agent was successfully grafted on cellulose nanocrystals. Modi ed CNCs demonstrated an excellent tensile strength (2190 MPa) and modulus (16.00 MPa), as well as storage modulus (1622 MPa) exhibited by 1wt% modi ed cellulose nanocrystals composites. Additionally, modi ed CNCs displayed hydrophobic behavior (CA=102 ± 2°). The corresponding modi ed CNCs have signi cant applications in combination of high stiffness and strength to the epoxy resins. This study lays a foundation towards full bio-based, environment friendly polymers fabrication and consumptions most desirable in adhesive and mechanical industrial elds.
Composites Part A: Applied Science and Manufacturing, 2018
Low resistance to organic solvent attack is still a limitation in cellulose-derived polymer applications. In this work, cellulose acetate/cellulose nanocrystal composites were prepared using a bifunctional molecule, (3-Isocyanatopropyl)triethoxysilane, as a crosslinking agent. The hydrolysis-condensation of the silane agent also resulted in the formation of a polysilsesquioxane network. The composite molecular structure, thermal behavior, and morphology were investigated by infrared spectroscopy; 29 Si nuclear magnetic resonance; dynamic-mechanical analysis; and scanning and transmission electron microscopies. The morphological analyses of the composites indicated that the polysilsesquioxane domains and cellulose nanocrystals were uniformly distributed throughout the homogeneous crosslinked matrix. The effect of CNC addition and polysilsesquioxane network formation on the composite swelling and dimensional stability was remarkable, particularly for composites containing the highest CNC content.
Adhesion and Surface Issues in Cellulose and Nanocellulose
Journal of Adhesion Science and Technology, 2008
This paper provides a review of the scientific literature concerned with adhesion and surface properties of cellulose and nanocellulose. Cellulose is the most abundant chemical compound on earth and its natural affinity for self-adhesion has long been recognized. The ease of adhesion that occurs in cellulose has contributed to its use in paper and other fiber-based composite materials. Cellulose adhesion, which has received considerable attention over the past half century, occurs over a practical length scale ranging from the nanoscale to millimeters. Adhesion theories that have been examined in the bonding of cellulose fibers include: mechanical interlocking, adsorption or wetting theory, diffusion theory, and the theory of weak boundary layers. Cellulose fibers on the nanoscale are prepared in four different ways: (1) bacterial cellulose nanofibers, (2) cellulose nanofibers by electrospinning, (3) microfibrillated cellulose plant cell fibers and (4) nanorods or cellulose whiskers. Structure and properties of nanocellulose that are important include: morphology, crystalline structure, surface properties, chemical and physical properties, and properties in liquid suspension. Cellulosic nanofibers present a very high surface area which makes the adhesion properties the most important parameter to control for nanocomposite applications. In this paper, we will focus on discussion of the adhesion and surface characteristics of cellulose nanofibers that impact its properties and application in nanomaterials. Koninklijke Brill NV, Leiden, 2008
Key Engineering Materials, 2018
Surface treated parawood microcrystalline cellulose (PW-MCC) performed under mechanochemical reaction using planetary ball milling at ambient temperature was used as a reinforcing material in polypropylene composites. Initially, PW-MCC was prepared by acid hydrolysis of parawood sawdust pulp. After that, PW-MCC was treated with vinyltrimethoxysilane at milling speed 400 rpm for 60 min. The surface composition from XPS indicated the existence of silicon atom on silane-treated PW-MCC. The thermal stability of PW-MCC was also improved and SEM micrograph revealed rough surface after modification reaction. The untreated PW-MCC and treated PW-MCC were applied to prepare polypropylene composites at 5-30 wt% loading content without a compatibilizer. The results demonstrated that silane-treated PW-MCC/PP composites enhanced tensile strength, thermal stability and water resistance of the composites.
2020
As one of the high-value and environmentally friendly chemical products, cellulose-based adhesive substance has been widely developed recently due to its extraordinary adhesion, interfacial flowability and high stability, along with low-impact side effects, outstanding degradability and biocompatibility. Also, microcrystalline-shaped cellulose has been fully exploited in functinalizing modification engineering. To eliminate the gap in application of cellulose-ether-based adhesion, we fabricated a new category of optimized cellulose sulfate product based on a system of analysis of key experimental factors: solvent pretreatment, degree of esterification, type and morphology of cellulose. Additionally, we focused on an all-round family of performance test of our product, containing characterization of structural and morphological features, test of water-based properties and inspection of adhesion behaviour. Within, the effect of adhesive strength in various solvents and under various c...
Biomacromolecules, 2018
A critical aspect in materials design of polymer nanocomposites is the nature of the nanoparticle/polymer interface. The present study investigates the effect of manipulation of the interface between cellulose nanofibrils (CNF) and poly(methyl methacrylate) (PMMA) on the optical, thermal and mechanical properties of the corresponding nanocomposites. The CNF/PMMA interface is altered with a minimum of changes in material composition, so that interface effects can be analyzed. The hydroxyl-rich surface of CNF fibrils is exploited to modify the CNF surface, via an epoxide-hydroxyl reaction. CNF/PMMA nanocomposites are then prepared with high CNF content (~38 wt.%) using an approach where a porous CNF mat is impregnated with monomer or polymer. The nanocomposite interface is controlled by either providing PMMA-grafts from the modified CNF surface or by solvent-assisted diffusion of PMMA into a CNF network (native and modified). The high content of CNF fibrils of ~6 nm diameter leads to strong interface and polymer matrix distribution effects. Moisture uptake and mechanical properties are measured at different relative humidity conditions. The nanocomposites with PMMA molecules grafted to cellulose exhibited much higher optical transparency, thermal stability and hygro-mechanical properties than the control samples. The present modification and preparation strategies are versatile, and may be used for cellulose nanocomposites of other compositions, architectures, properties and functionalities.